Eyes closing/opening post processing material

Hi,

I am looking for help with creating post processing material for eyes closing/opening. I would like my material to mask those black areas in the world.

Here is what I have so far:

Thanks in advance!

I assume you probably just want to Lerp between scene color and black?

Something like this should work:

Or this for smoother transition:

Thank you very much! Do you know how to create good gradient for eyes? I ve placed my gradients in first post but they does not work well. I would like to create similar gradient to Mask (G) but curved to simulate eyes shape.